Dysregulation of proteases in cancer has important consequences in cell signaling and helps drive cancer cell proliferation, invasion, angiogenesis, avoidance of apoptosis, and metastasis. Currently, in vivo analysis of proteases (and other enzymes such as glycosidase, esterase, etc.) activity is limited to biopsy or local fluorescent techniques, which are hindered by their invasiveness or low multiplexing potential, respectively.